Hydration Effect on Curcumin Inclusion by Native Cyclodextrins

The inclusion compounds of curcumin with hydrated and anhydrous native α-, β- and γ-cyclodextrins were prepared by ball milling. Milling a 2 : 1 mixture of the cyclodextrins and curcumin resulted in the complete inclusion of this guest when using anhydrous cyclodextrins according to the data of TG/DSC analysis, powder X-ray diffraction and FTIR spectroscopy. The hydration of cyclodextrins up to the saturation level gives a slight decrease of the curcumin inclusion extent. The prepared inclusion compound of curcumin and β-cyclodextrin in milled form exhibits a unique exothermic cold crystallization effect. The high thermal stability of the inclusion compound allowed its fusion without decomposition at fast heating rates of 10 000 K/s, and its melting point was determined. This is the first example of such successful experiment for an inclusion compound of native cyclodextrin.